int cliques = 0;
void setup() {
  size(600,600);
  background(255);
  stroke(255,0,0);
  strokeWeight(20);
  fill(255,0,0);
}
void mouseClicked() {
  cliques = cliques + 1;
  if (cliques > 6) cliques = 0;  
}
void draw() {
  background(255);
  switch(cliques) {
    case 6:
      ellipse(300,100,100,100);
    case 5:
      line(300,100,300,300);
    case 4:
      line(200,200,400,200);
    case 3:
      triangle(300,250,400,400,200,400);
    case 2:
      line(250,400,250,500);
    case 1:
      line(350,400,350,500);
  }
}
